BEIRUT (AP) -- Clashes between members of al-Qaida's branch in Syria and a rebel faction in the country's north believed to have been trained by the U.S. government have stopped after the rebels abandoned their headquarters, activists said Saturday.

The Nusra Front meanwhile released a video showing one of the captured rebels saying that the men in the faction known as Division 30 were trained in Turkey by U.S. officers and sent back to Syria with money and weapons.

The fighting came a few days after the U.S. and Turkey announced the outlines of a deal to help rebels push the Islamic State group back from a strip of territory it controls along the Syrian-Turkish border, replacing it with more moderate rebels backed by Washington and Ankara.

Rami Abdurrahman, who heads the Britain-based Syrian Observatory for Human Rights, said members of the Division 30 faction fled to a nearby area controlled by a Syrian Kurdish militia. Abu al-Hassan Marea, a Syrian activist who is currently in Turkey near the Syrian border, confirmed Saturday that Division 30 fighters have withdrawn from their headquarters.

Abdurrahman and Marea said Division 30 had less than 60 fighters and that on Friday alone the group lost five fighters and 18 others were wounded.

A representative of Division 30 did not respond to written questions sent to the group's Facebook account.

On Friday night the Nusra Front said it attacked Division 30 and abducted some of its members, including its commander, because they were trained by the CIA and vowed in a statement to cut off "the arms" of the American government in Syria. During the fighting, U.S.-led coalition warplanes attacked the Nusra Front fighters according to activists.

On Saturday Nusra Front posted a video showing the operation in which several Division 30 members were captured and the aftermath of the U.S.-led coalition airstrike. Five men were seen being taken with their hands behind their heads.

One of the alleged rebels captured by Nusra Front identified himself as Zakaria Ahmad Safsouf from the northwestern village of Jbala saying he was asked by a rebel commander to go to Aleppo where he guarded a post. He said that after spending between 10 to 20 days in Aleppo, fighters were sent to Turkey for a 45-day training program that ended with each rebel being given an M16 assault rifle as well as $400 and 400 Turkish Liras ($150).

"They then send them back to Syria to fight the Nusra Front," the man, with a light beard said while standing in front of what appeared to be sand bags in a field. "There are senior American officers and telecommunications equipment so that (rebels) communicate with the coalition."

A masked Nusra Front fighter also appeared in the video saying his group has "cut of the hands of the West and Americans."

A U.S. military official seemed to deny any American connection to Division 30, saying on Friday that no member of a U.S.-backed rebel faction had been abducted.

Also Saturday, Syria's state media and the main Kurdish militia in the country said government forces and Kurdish fighters have captured the last pocket that was held by the Islamic State group five weeks after the extremists stormed the city and captured several southern neighborhoods.

"Out units were able to fully liberate the city of Hassakeh from Daesh's mercenaries and were able to evict them from the city," said a statement from the Kurdish People's Protection Units, or YPG, using an Arabic acronym of the Islamic State group.

Syria's state news agency said Syrian troops "have wiped out that last den of Daesh's terrorists" in Hassakeh.

Hassakeh had been controlled by Syrian troops and Kurdish militia until IS fighters stormed the city in late June.

The YPG has been the main force fighting against IS in Syria under the cover of airstrikes by the U.S.-led coalition.

In central Syria, troops captured several areas and a power station they lost last year in battles with militants including Nusra Front fighters, according to the Observatory and state media. The Observatory said 27 insurgents have been killed since Friday.

Syria's civil war, now in its fifth year, has killed more than 220,000 people and wounded more than a million.